Circuit for speeding the operation of a relay

ABSTRACT

The operation of a relay is speeded up by placing its windings in series with the energized windings of a second relay. Collapse of the magnetic field in the windings of the second relay produces an EMF which is greater than that normally available for the operation of the first relay thereby causing the first relay to be energized with a higher potential, and to operate more quickly.

United States Patent Malm I v 151 3,666,997 [451 May 30, 1972 [54]CIRCUIT FOR SPEEDING THE OPERATION OF A RELAY [72] Inventor: MarvinForrest Malm, Milan, Tenn. [73] Assignee: International Telephone andTelegraph Corporation, New York, NY.

221 Filed: on. 30, 1970 21 Appl. No.: 85,519

52 user .,.3 l7/l23,l79/l86E,3l7/DIG.6

[51] lnt.Cl. "noun/22 5s .FieldoiSearch ..307/l43;3l7/DlG.6,l23;179/1865 [5 6] References Cited UNITED STATES PATENTS 2,951,186 8/1960Dickinson..... ..l.. ..3l7/D!G.6

3,149,244 9/1964 Bamesetal. "lam/mos Primary Examiner-Robert K. SchaeferAssistant Examiner-William J. Smith Attomey-C. Cornell Remsen, Jr.,Walter J. Baum, Paul W. Hemminger, Charles L. Johnson, Jr., James B.Raden, Delbert P. Warner and Marvin M. Chaban ABSTRACT The operation ofa relay is speeded up by placing its windings in series with theenergized windings of a'second relay. Collapse of the magnetic field inthe windings of the second relay produces an EMF which is greater thanthat normally available for the operation of the first relay therebycausing the first relay to be energized with a higher potential, and tooperate more quickly.

6 China, 2 Drawing figures CIRCUIT FOR SPEEDING THE OPERATION OF A RELAYThis invention relates to a circuit for increasing the speed at which arelay may be operated.

In the prior art, 'to increase the speed at which a relay operates, useis sometimes made of a capacitor which is charged to a higher voltagethan the voltage normally required for operation of the relay; Thecharged capacitor is then dischargedthrough the relay, causing a morerapid build-up of the magnetic field in the relay windings than wouldotherwise occur and thereby reducing the time required for operation ofthe relay.

Usage of a capacitor to speed-upthe operation of a relay in this mannerhas several disadvantages in a switching system. These disadvantagesinclude requirements for additional equipment, such as a special highvoltage supply, a capacitor which is an extra component, and a morecomplicated switching arrangement.

It is a primary object of the present invention to overcome theforegoing disadvantageswhile assuring faster operation of a relay andcircuits dependent upon operation of the relay. In orderto attain theforegoing objects and overcome the objectionable features of the priorart, the present invention employs energy stored in one relay coil, orinductor, to overcome the normal inductive opposition to build-up ofenergy in a coil or inductor of a second relay. Thisprocedure greatlyreduces the build-up time required for the magnetic field, therebycausing the second relay to operate faster.

The abovementioned and other features and objects of this invention andthe manner of obtaining them will becomemore apparent, and the inventionitself will be best understood by I reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, in which:

- FIG. 1 illustrates an embodiment of the invention in a simplified formto show the principles employed, and

FIG. 2 illustrates an embodiment of the invention as it may be appliedin a particular circuit. Turn now to FIG. I for a disclosure of theprinciples of the invention as they apply to a preferred embodiment ofthe invention. In this Figure, a relay A and a relay B are shown to beinterconnectable between a terminal 2 and ground through a number ofswitching circuits indicated by blocks at 4, 6 and 8. It should be notedthat in using the invention with telephone circuits and the like therewill be complete connections through appropriate switching elements (notshown) in blocks 4, 6 and 8. Continuity between parts of the lineisindicated by dashed lines within the blocks 4, 6 and 8.

In discussing the invention as embodied inFIG. 1, let us assume a casein which connections are completed by telephone switching circuits at 4and 6 using conventional means outside the scope of the presentinvention. Under these circumstances, relay A will be operated by theapplication of a negative voltage from the terminal 2 via circuits 4 and6 and the break contact c to ground. In the operated state, the windingsof relay A serve as energy storage inductors.

Assume further that by normal means (not shown) ground is connectedthrough the switching elements at 8 and through the coil at B to theterminal 10. Subsequently, the contact is opened. Current from terminal2 will then be diverted to flow from terminal 10 through the coil inrelay B and the switching circuit 8 to ground. At this time, however,the inductive reactance presented by the coil of relay B will oppose theflow of current. This causes the flow of current to be limited and themagnetic field in the winding of A to begin to collapse. In

collapsing, the magnetic field in the winding of A generates a counterEMF which increases the voltage at 10 and, therefore, the voltageappearing across the winding of relay B. This higher voltage tends tooffset the effects of the inductive reactance in the winding of B,forcing the magnetic field in B to build up much more rapidly than itotherwise would and sharply reducing the time lag caused by inductivereactance in the winding of the relay B.

In the circuit of FIG. 1, RC suppression is provided by R1 the S relayis reduced about 40 By use of this invention in the register circuitreferred to v and CI in the event the inductive kick voltage reachesbreakdown levels of the insulation of any components involved. SelectedR1 and Cl components have an insignificant effect on timing. If relay Bis to release in the normal time, a diode D1 will be connected betweenpoint 12 and ground. Alternatively, with a ground connection directly toterminal 12, the relay B will be slow to release.

Turn now to FIG. 2 for an illustration of a portion of a registercircuit employing the principles set forth above in relation to FIG. 1.In FIG. 2, a line relay L is shown. This relay may be used in dialpulsing through opening and closing contacts 20 in a conventionalmanner. A hold relay H is used in the completion and maintenance ofcertain circuits of the res st mammary. Qintihrln ths q axsrsrf n usualfunctions in a dial system. 1

The speed of operation of the S relay is increased through use of theprinciples of this invention. As a result, the operation of the registeris improved. To accomplish this improvement, the following sequence ofevents is followed using components such as are shown in FIG. 2. Onseizure, occasioned by application of a potential at terminal 22, the Lrelay operates closing make contact I1 and causing the H relay to beoperated by a potential directed between terminal 24 and ground. RelayH, in operating, closes make contacts hl, I12 and k3 and locks itselfbetween a potential at 30 over R1 and make contact h3 to ground. At thistime, the ground potential available through contact 11 is extendedthrough the contacts hl and k2. The potential at both sides of theS-relay coil is at ground, thus making relay S inoperative. At the sametime, the relay AH is operated by the potential over its winding betweenterminal 28 and ground. Operation of relay AH causes certain functionsto be performed through closure of contacts which are not shown inaddition to opening the operate path of relay H. Upon being operated,energy is stored in the magnetic circuit of relay AH.

When a digit is dialed and the L relay drops at the start of the firstpulse, the contact l l are opened and the short is removed from the Srelay, allowing it to operate via the AH winding to the potential atpoint 28. The operation of the S relay is speeded up due to the energyfrom the field of the relay AH. The inductance in the coil of the Srelay opposes a change in current which normally causes a lag in heldbuild-up and a corresponding lag in relay operation. How ever, using theillustrated circuit in accordance with the invention, the AH relay alsoexhibits opposition to change due to the inductance of its coil. As thefield in the AH relay collapses it generates a voltage which causes arapid buildup in the S relay field thereby reducing the fieldbuild-uptime to a low'level. As a consequence, the operate time of above, twopower resistors can be eliminated from the register circuit. At the sametime the performance of the S relay, and consequently of the register,is improved without adding other expensive components.

The principles of this invention may be used in selected circuits when arelay must operate faster than normal. The invention does not requirethe use of a high voltage supply or extra components.

While the principles of the invention have been described above inconnection with specific apparatus and applications, it is to beunderstood that this description is made only by way of example and notas a limitation on the scope of the invention.

I claim:

l. A circuit for increasing the speed of operation of a relay, compnslngfirst and second relays, and

switching means including a plurality of relay contacts for couplingwindings of said first relay in series between a source of potential anda terminal and through the terminal to a first ground connection toproduce a magnetic field in said windings of the first relay,

said switching means including contacts for coupling the second relay inseries between the terminal and a second ground connection,

said switching means including contacts for decoupling the first relayand the terminal from the first ground connection to enable the magneticfield in the first relay to begin to collapse, thereby generating apotential augmenting the potential from the source of potential to speedthe energization of the second relay.

2. A circuit as claimed in claim 1, in which the switching means forcoupling the first relay between a source of potential and a firstground connection includes a line relay responsive to seize signals toprovide the initial coupling over make contacts.

3. A circuit as claimed in claim 1, in which the switching means forcoupling the windings of the first relay through the terminal to a firstground connection includes a line relay responsive to seize signals toprovide a partial coupling aof arelaynd a hold relay operated by theline relay to complete the coupling. 4. A circuit as claimed in claim 3,in which the line relay is coupled to respond to dial pulses and therebyalternately energize and release the first relay by completing andbreaking connections between the source of potential and ground.

5. A circuit as claimed in claim 1,'in which said switching means forcoupling said first relay to a first ground connection includes contactsof a line relay and of a hold relay which couple the windings of thesecond relay between the first and the second ground connections.

6. A circuit as claimed in claim 3, in which the line relay is coupledto respond to dial pulses and thereby to alternately close, and open itscontacts,

said line relay operating when its contacts are open to disconnect thefirst ground connection and to apply the potential across the windingsof the second relay, thereby causing a collapse in the magnetic field ofthe first relay and inducing a high voltage in the windings of thesecond

1. A circuit for increasing the speed of operation of a relay,comprising first and second relays, and switching means including aplurality of relay contacts for coupling windings of said first relay inseries between a source of potential and a terminal and through theterminal to a first ground connection to produce a magnetic field insaid windings of the first relay, said switching means includingcontacts for coupling the second relay in series between the terminaland a second ground connection, said switching means including contactsfor decoupling the first relay and the terminal from the first groundconnection to enable the magnetic field in the first relay to begin tocollapse, thereby generating a potential augmenting the potential fromthe source of potential to speed the energization of the second relay.2. A circuit as claimed in claim 1, in which the switching means forcoupling the first relay between a source of potential and a firstground connection includes a line relay responsive to seize signals toprovide the initial coupling over make contacts.
 3. A circuit as claimedin claim 1, in which the switching means for coupling the windings ofthe first relay through the terminal to a first ground connectionincludes a line relay responsive to seize signals to provide a partialcoupling and a hold relay operated by the line relay to complete thecoupling.
 4. A circuit as claimed in claim 3, in which the line relay iscoupled to respond to dial pulses and thereby alternately energize andrelease the first relay by completing and breaking connections betweenthe source of potential and ground.
 5. A circuit as claimed in claim 1,in which said switching means for coupling said first relay to a firstground connection includes contacts of a line relay and of a hold relaywhich couple the windings of the second relay between the first and thesecond ground connections.
 6. A circuit as claimed in claim 3, in whichthe line relay is coupled to respond to dial pulses and thereby toalternately close and open its contacts, said line relay operating whenits contacts are open to disconnect the first ground connection and toapply the potential across the windings of the second relay, therebycausing a collapse in the magnetic field of the first relay and inducinga high voltage in the windings of the second relay.